10.1.2.1 VC++ Environment Variables

There is a batch file in your VC++ installation's bin directory called
vcvars32.bat, which sets up the environment variables needed to
run the VC++ command line tools. Arrange for those same environment
variables to be set in your Emacs session. You can do this on Windows
9x by calling the vcvars32.bat script from autoexec.bat.
On other versions of Windows you can set the environment variables
globally using the System control panel.

For all versions of Windows you can alternatively set the variables
just inside Emacs by using setenv calls in your init file.
See Where do I put my init file?.

You should now be able to compile from Emacs. Load a source file from
a VC++ project. Type M-x compile. Replace the proposed command line
with:

nmake -f ProjectName.mak

You will find that this defaults to a debug build. You can change it
to a release build with: